DocID10973 Rev 2

13/25

AN2067

Switching cycle

25

5

Switching cycle

Figure 4 and Figure 5 show the drain voltage and drain current respectively in discontinuous

mode and continuous mode, with a 40 W static load, and input voltage respectively at 400 V

voltage in burst mode. The output (static) load is 4 W (40 V, 100 mA), and input voltage is

respectively at 100 V and 400 V.

Table 2. Transformer specifications

Parameter

Turn ratio

Number

of turns

Number

of wires

Wire (mm)

Max. current

(A)

Primary inductance

Lprim: 0.5 mH Lleak < 4

µH (0.8%) core: E25H

52

2

0.4

2.3

Primary auxiliary winding

0.211

11

1

~0.2

<0.1

Secondary winding

0.5

26

1

0.7

1

Secondary auxiliary winding

0.077

4

1

~0.2

<0.1